[BUGFIX] Allow search terms with large special chars

This patch ensures that search term like Ärmel and Æble
is also working. Currently the match didn't work if a
uppercase special char was used.

With the additional modifier, this is now working, and
there will be matches on both lowercase and uppercase
matching words.

Resolves: #97986
Releases: main, 11.5, 10.4
Change-Id: If7ff1669ead57557964ed5372c4af749c316d7bf
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76894


Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Stefan Bürk <stefan@buerk.tech>